18. Gavin Rossdale and Gwen Stefani

Rock stars like to say it's all about the music, but for Gwen Stefani and Gavin Rossdale, it's clearly also about the gym, too. Staying active helps the pop star and her husband, the former Bush front man, endure long stretches on the road while touring.

Just don't get expect to find Stefani practicing her downward dog backstage. "I'm not into yoga or pilates," she told Elle. "They don't work for me, and I don't have the patience. I'm more like a man: I like going to the gym and lifting weights or doing a little boxing."

The singer also avoids junk food, preferring a mix of organic veggies, fruit, soy milk, and peanuts. (Discover the amazing benefits of almonds and other super-foods).

When he's not on the road with his own band, Rossdale plays the role of dutiful husband—something Stefani acknowledges in her lyrics. "I wrote in a song, 'You seem like you'd be a good dad,'" Stefani told People. "So, yeah he's lived up to my expectations. He has always been very loving and romantic."